This invention relates to magnetic data storage discs, and more particularly, to so-called "floppy discs."
In prior art floppy disc drives, the floppy disc has been rotated about its axis to create an arcuate movement of the floppy disc relative to the read/write head which is driven along a radial path across the floppy disc so as to place the read/write head in magnetic communication with the floppy disc in a plurality of concentric tracks on the disc. In other words, the rotational movement of the floppy disc moves the disc relative to the head through so-called sectors of the disc. In addition, the head is indexed in a generally radial path from concentric track to concentric track of the floppy disc.
Heretofore, the radial movement of the read/write head has been achieved by rotary stepper motors in combination with appropriate mechanical apparatus for translating rotational movement into linear movement. A drive of this type is incorporated in the floppy disc system manufactured by Shugart Associates of Sunnyvale, California Linear motors of the voice-coil type have been incorporated in the head drive of large magnetic storage discs other than the floppy type. See U.S. Pat. No. 3,521,092 to Kalthoff.
"Theory and Application of Step Motors," edited by Benjamin Kuo, West Publishing Co., 1974, discloses the use of linear stepper motors rather than rotary stepper motors in combination with rotary-to-linear motion translators. A number of different types of stepper motors are also disclosed therein. Linear stepper motors for various uses or applications are also disclosed in copending application Ser. No. 809,646 filed June 24, 1977, Ser. No. 833,271 filed Sept. 14, 1977, Schreiber et al U.S. Pat. No. 3,162,796 and Chai U.S. Pat. No. 3,867,676.